The invention relates to liquid fuel indoor and outdoor fire displays, particularly burner assemblies configured to burn a liquid fuel, such as an alcohol, paraffinic oils, plant oils, and flammable petroleum products, either in a liquid or gel form.
Historically, alcohol burning hearth products (fireplaces, stoves, log sets, vessels for containing open flames, etc) comprise a burner that is filled with alcohol, usually a denatured ethanol, or in the alternative, cans of flammable gelled alcohol, that are then lit to create the flame. Depending on the configuration of the burner and the size of the fuel reservoir, once ignited the fuel will burn until consumed, generally for 1-4 hours. Some burner configurations include a damper that will allow the flame to be extinguished prior to full consumption by covering the flame and restricting access to air. To extend the burning time the user typically has to wait until the fuel has burned completely, or the flame is extinguished, and the burner has cooled down before adding more flammable liquid or replacement can of gelled fuel into the burner and lighting it again. This procedure presents a number of problems which include:                a) The possibility of spilling a highly volatile and flammable fluid on the fireplace or stove assembly and log set, which presents the possibility of unintended combustion thus creating an unsafe situation;        b) Spilling the fuel on a person's arm, clothing or on the floor which can also create a fire hazard;        c) Because the fuels are highly volatile, and it is the vapors off the fuel and not the liquid fuel itself that is burning, these vapors present a very serious risk of accidental ignition. This hazard requires the user to wait for the flame to extinguish and the burner to cool down before refueling to prevent vaporized fuel from spontaneously igniting during the filling process;        d) Additionally, ethanol, unless specifically blended with additives to provide a visible flame, tends to burn with a nearly invisible color, especially in well-lit areas, causing spills to be very dangerous since it is sometimes impossible to notice that the fuel has ignited. Certain burner assemblies are designed to create yellower flames that are more visible, especially after the fuel has been ignited for some time; the conditions that make the flame visible in the burner assembly do not exist to allow visualization of burning fuel spills;        e) The fuel level inside the burner of an ethanol burning assembly is constantly changing as the fuel is consumed and thus is not always at an optimum level for aesthetics or for clean combustion of the fuel.        
These liquid fuel burners in many instances are used as unvented appliances in unvented spaces. As a result, the emissions from combustion end up in the room. Thus clean and complete combustion is very important. An improperly designed or operated liquid fuel burner, or the use of the wrong liquid fuel, can release fuel vapors and carbon monoxide into the room. As a result, consumers have been reluctant to use the currently available ethanol burners.
One product provides for pouring fuel into a reservoir that is then slid into the fireplace assembly from outside the burner assembly. However, this design still requires pouring the fuel from an open bottle, allows for the release of flammable vapors and does not safely allow additional fuel to be added while the fuel is burning.